Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Hair Treatment Compositions With Amine Derivatives
Field of the Invention
The present invention is in the field of hair treatment applications.
Specifically, it is
concerned with alternatives to ammonium hydroxide for softening and swelling
the cuticle of
the hair, and for enabling penetration of reagents and hair-benefit actives
into the cortex.
Background
Hair Structure
Human hair fiber is generally understood as having an outermost layer, called
the
cuticle. The cuticle comprises about 6-12 layers of overlapping, flattened
keratinocytes that
are arranged in a "fish scale" arrangement in the longitudinal direction of
the hair fiber. The
overlapping cellular arrangement permits the cells to slide past each other,
which gives hair
fibers a high degree of flexibility without breaking. The cuticle layers also
regulate the
amount of water within the hair shaft The outermost surface of the cuticle is
coated with a
lipid substance that renders the surface of the hair hydrophobic. Also, the
fish scale
arrangement of the cuticle and the lipid coating confer barrier properties to
hair fiber. A
second layer of hair fiber, below the cuticle, is the cortex. Natural dye,
called melanin, is
found here. Due to the semi-transparent nature of the cuticle, the melanin in
the cortex is
normally visible. The cells of the cortex form a matrix that supports keratin
protein structures.
In the cortex, protein filaments made of long keratin chains are the main
structural component
of hair. These keratin chains are rich in the sulfur-containing amino acid,
cysteine, which
forms permanent, thermally stable crosslinking in the form of disulfide
bridges between
keratin chains. Human hair is approximately 14-20% cysteine. The extensive
disulfide
bonding of cysteine gives hair approximately one-third of its strength, and
makes hair
generally insoluble, except in specific dissociating or reducing agents.
Softening the Cuticle
The present invention is concerned with softening and swelling the cuticle of
the hair,
for any purpose, such as, but not limited to relaxing, straightening, perming,
strengthening and
coloring the hair. In various types of hair treatment where swelling and
loosening of the
cuticle is required, ammonia (in solution) is considered the 'gold standard'.
Ammonium
hydroxide, an alkalizing agent, raises the pH of hair, causing the hair
cuticles to swell and
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loosen so that actives and/or reagents can penetrate into the hair. However,
the use of
ammonia has a number of drawbacks. For example, when in use, ammonia gas
readily
escapes into the ambient environment, giving off a strong malodor, as well as
irritating the
skin, eyes, nose and throat. These adverse effects may be experienced by the
person whose
hair is being treated, as well as by the person providing the treatment. Also,
ammonia is
known to cause damage to the hair through breaking of peptide bonds. For this
reason,
research into alternative cuticle penetration methods has been ongoing for
several decades,
with mixed results. For example, because of their low odor, aminomethyl
propanol (AMP)
and monoethanolamine (MEA) have been used as replacements for ammonium
hydroxide.
Both molecules are known to be used in cosmetic formulations as a pH buffer.
In terms of
their action on hair, the amine functional group, NH2, reacts similarly to
ammonia (NH3) in an
ammonium hydroxide solution, while significantly reducing the ammonia odor.
Nevertheless,
a substantial increase in hair fiber damage has been associated with AMP and
MEA, and this
remains a major concern in the field. In fact, until now, no treatment has
been found that is as
effective at opening up the cuticle as ammonium hydroxide, while also avoiding
or
significantly reducing the adverse effects of malodor and excessive hair
damage.
Hair Coloring Treatments
While the principles of the invention may pertain to various types of hair
treatments,
the invention is described herein, in terms of hair coloring treatments.
Coloring of human hair is a very popular cosmetic treatment. Presently, there
are four
basic types of hair color treatments, classified according to color retention.
Temporary and
semi-permanent are non-oxidative treatments that employ colored dyes that are
deposited on
the surface of the hair cuticle. Temporary hair dyeing is used to color their
hair for a short
time, such as one day. This type of hair color may be achieved with basic
dyes, acid dyes,
disperse dyes, pigments or metallized dyes. Unable to penetrate the hair due
to their molecular
size, and with little affinity for the hair, temporary dyes typically wash out
with a single wash.
In contrast, semi-permanent dye molecules are smaller, and may display some
affinity for the
hair. The smaller size allows the dye to penetrate into the cuticle, and it is
even possible that
some of the dye will reach the cortex. Nevertheless, an alkalizer is sometimes
used in semi-
permanent treatments to facilitate penetration through the cuticle. For this
reason, the present
invention may find use in semi-permanent hair coloring. As a result of
penetrating the cuticle,
semi-permanent dyes require about six to twelve shampoos to rinse out.
Temporary and semi-
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permanent hair coloring products are available as lotions, gels, shampoos,
liquid solutions,
emulsions and mousses.
Permanent hair color treatments provide color that does not wash out with
shampooing,
and lasts effectively until the treated hair is grown out. The "dyes" in
commercial coloring
products are actually colorless dye precursors that are small enough to
migrate under the
swollen cuticle, and diffuse into the cortex. Inside the hair cortex, the
precursors undergo a
series of redox reactions to develop the final color. In the field of
oxidative hair dyeing, we
generally speak of two classes of dye precursor molecules: oxidation bases
(also known as
primary intermediates) and reaction modifiers (also known as couplers or
secondary
intermediates). By design, the redox potential of the primary intermediate is
more favorable
for oxidation than the secondary intermediate, such that the primary
intermediate will be
oxidized first. The weaker oxidation potential means that secondary
intermediates alone are
capable of producing only slight coloring, but may be used to contribute
highlights. Primary
intermediates oxidize to highly reactive species that proceed to react with
the electron-rich
secondary intermediates to form a colorless transient intermediate, called a
leuco dye. The
leuco dye is rapidly oxidized to a final_ colored conjugated dye. Due to their
size, the
conjugated dye molecules resist being rinsed out of the cortex.
In general, the primary and secondary intermediates are of three aromatic
types:
aromatic diamines, aminophenols, and phenols. The primary intermediates are
aromatic
diamines and aminophenols where the substituted amino or hydroxy group is
located in the
para or ortho position, with respect to the amino group. This positioning
confers the property
of easy oxidation. Primary intermediates are capable of forming quinone, semi-
quinone, and
imin-quinone structures. Examples of compounds that have found use as primary
intermediates include: p-phenylenediamine (PPD), 2-methyl-p-phenylenediamine
(PTD), p-
aminophenol (PAP), 1,4-dihydroxybenzene, N,N-bis-(2-hydroxyethyl)-p-
phenylenediamine,
4,5-diamino-1-(2-hydroxyethyl) pyrazole, 2,4,5,6-tetraaminopyrimidine, o-
aminophenol,
catechol, and 1,2-benzediamine, and others. Common modifiers are aromatic m-
diamines, in-
aminophenols, and m-polyphenols. With substituents in a meta position, these
molecules are
less easily oxidized. Examples include: m-phenylenediamine, 2,4 resorcinol-
diaminoanisole,
m-chlororesorcinol, m-aminophenol, resorcinol, 2-methyl resorcinol, 1-
naphthol, 4-amino-2-
hydroxytoluene, and 1,3-benzenediamine.
Two other essential components of an oxidative hair dye system are the
alkalizing
agent and the oxidizing agent. Both perform multiple functions. For example,
as noted above,
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dye precursors must be able to penetrate into the hair cortex. To facilitate
that process, an
alkalizing agent (usually ammonium hydroxide) is used to soften and swell the
cuticle. In
addition, the alkalizer also raises the pH of the cortex environment (to about
pH 9-11) which
enhances the reactivity of the oxidizing agent. The oxidizing agent (also
known as a
developer, usually hydrogen peroxide, H202) oxidizes the primary intermediate
to initiate a
cascade of oxidation reactions that transform colorless precursor dyes into
the final colored
complex. At the same time, however, the alkalizing agent converts some of the
H202 to 00H-
. 00H- is a very reactive depigmenting reagent that neutralizes natural hair
melanin or any
previously applied oxidative hair color, so that the newly applied color can
show through
without distortion.
Demi-permanent hair coloring is another treatment where the present invention
will
find application. Demi-permanent hair color, which lasts for about 20-24
shampoos, occupies
an intermediate position between semi-permanent and permanent hair color. Demi-
permanent
hair color treatments utilize a mix of semi-permanent dyes and dye precursors
typical of
permanent color treatments. The dyes are mixed with an alkalizing agent (such
as
monoethanolamine MEA or aminomethylpropanol AMP) that swells the cuticle less
efficiently than ammonia. Colorless dye precursors penetrate the outer
cuticle, and some is
able to enter the cortex, where the precursor molecules then combine to create
larger color
molecules that resist being washed out. As in permanent dyeing, hydrogen
peroxide is used,
but at lower concentrations. As a result, the pre-existing hair color is not
appreciably lifted.
Therefore, this type of dye works well for adding darker colors to hair.
Summary
The present invention is concerned with compositions and methods for softening
and
swelling the cuticle of the hair. The compositions comprise certain amine
derivatives that
feature electron donors/acceptors, making them useful as keratin compatible
alkalizing agents
for softening and swelling the cuticle of the hair.
Description of the Figure
The lone figure displays data of the denaturation temperature of an alkalizer
composition comprising a combination of 2-Dimethyl-amino-2-methyl-1-propanol
(DMAMP)
and NH3.
Detailed Description
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Except where otherwise explicitly indicated, all concentrations of materials
and
conditions of reaction, are to be understood as modified by the word "about."
All concentrations are presented as percentages by weight of the final
composition,
unless otherwise specified.
The term "comprising" and the like, mean that a list of elements may not be
limited to
those explicitly recited.
Specific examples set forth herein are illustrative only, and the present
invention is not
limited to those mentioned examples.
Alkalizing Agents
It can be shown that certain C3-C6 alkanolamines that feature electron
donors/acceptors (as the case may be) are useful as alkalizing agents in
oxidative and non-
oxidative hair coloring applications, either alone or in combination.
Alkanolamines are
comprised of an alkane backbone that has amino and a hydroxyl functional
groups. These
relatively large, organic molecules are not as volatile as ammonia. However,
like ammonia,
alkanolamines, in general, are able to create a strongly basic environment
that is potentially
damaging to hair and skin cells. It is generally thought that the amine group
is responsible for
damage to the hair. In fact, depending on the concentration required to
reproduce the benefits
of ammonia in hair treatment applications, some alkanolamines may produce more
or less
odor and damage than ammonia. Eleven alkalizing agents that are of particular
interest, here,
are shown in Table 1 (not including ammonium hydroxide, MEA and AMP which are
included for comparison only).
Table 1 - Alkalizing Agents
Molecular
Structural formula for
Alkalizer Molecular Weight for
active pKa
([NCI name) formula active
component
component
Ammonium NH4OH H 17.03 9.24
hydroxide : It
Monoethanol- C2H7NO 61.08 9.50
amine
(MEA)
primary amine
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Aminomethyl C41-111NO 89.13
9.82
propanol
(AMP)
primary amine
2-Di methyl- C6H15NO 117.19
10.2
amino-2-methyl- HO)
1-propanol N
(DMAMP)
tertiary amine
2-Amino-2- C4IIIN02 105.14
8.80
methyl-1,3-
prop an e di ol
(AMPD)
primary amine
2-Amino-2- C5H13NO2 119.14
8.80
ethyl-1,3-
propanediol
(AEPD)
primary amine
3-Amino-1- C3H9NO 75.11
9.96
propanol
(AP)
primary amine
3-Dimethyl- C5H13NO 103.16
9.27
amino -1 -
propanol
(DMAP) tertiary amine
3-(Dimethy- C5H13NO2 119.16
lamino)-1,2-
propandiol
(DMAPD)
tertiary amine
3-Amino-1,2- C3H9NO2 91.11
propanediol
(lsoserinol)
primary amine
2-Amino-1,3- C3H9NO2 91.11
propanediol
(S erinol)
primary amine
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Diethanolamine C4FlioNO2 HO OH 105.14
8.88
(DEA) NH
secondary amine
Triethanolamine C6H15NO3 149.19
7.8
(TEA)
<
tertiary amine
Tromethamine C4FI11NO3 HO 121.14
8.1
(a.k.a. Tris)
Ho-c OH
NH2
primary amine
In determining which of these eleven compounds or combinations thereof may
offer
performance benefits over ammonia, aminomethyl propanol (AMP) and
monoethanolamine
(MEA). a study was made of the ability of each of the eleven compounds to lift
natural color
out of the hair, the degree of damage caused by applying the compounds to the
hair, and the
degree of malodor. These results will be discussed below.
In alkalizing compositions of the invention, the total amount of all
alkanolamine
alkalizing agents will typically range from about 0.001 to 25%; for example
from about 0.4%
to about 20%; for example from about 1% to about 15%; for example from about
2% to about
12.5%; for example from about 3% to about 10%. If ammonium hydroxide is used
in
combination with an alkanolamine identified herein, then the concentration of
ammonium
hydroxide should be limited to about 0.01% to 14%.
Oxidative Hair Dye Products
In practice, an oxidative hair-dye product consists of two containers, a first
containing
(I) an alkalizer composition, and a second containing (II) an oxidizing agent
composition.
These are mixed shortly before application to the hair. The mixture may be
referred to as the
on-hair product.
I. The Alkalizer Composition
Alkalizer compositions of the invention comprise an aqueous solution of one or
more
alkalizing agents shown in Table 1, and one or more oxidative dyes.
Optionally, various
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auxiliary ingredients may be included which impart a benefit to the alkalizer
composition or to
the hair.
Oxidative Dyes
Alkalizer compositions according to the present invention comprise one or more
primary intermediates that are operable, when combined with an oxidizing
agent, to impart
color to the hair. Optionally, the alkalizer compositions may also comprise
one or more
couplers.
Primary Intermediates
Primary intermediates may generally be present in the alkalizer composition in
amounts ranging from about 0.001 to 25%, preferably from about 0.005 to 20%,
more
preferably from about 0.01 to 15% by weight of the total alkalizer
composition. Such primary
intermediates include ortho or para substituted aminophenols or
phenvlenediamines, such as
para-phenylenediamines of the formula:
NRI R-2
R6 0 R3
R5 R4
NI-12
wherein R1 and R2 are each independently hydrogen, C1-6 alkyl, or C1-6 alkyl
substituted
with hydroxy, methoxy, methylsulphonylamino, furfuryl, aminocarbonyl,
unsubstituted
phenyl, or amino substituted phenyl groups; and R3, R4, R5, and R6 are each
independently
hydrogen, C1-6 alkyl, C1-6 alkoxy, halogen, or CI-6 alkyl substituted with one
or more amino
or hydroxyl groups. Such primary intermediates include para-phenylenediamine
(PPD), 2-
methy1-1.4-diaminobenzene, 2,6-dimethy1-1,4-diaminobenzene, 2,5-dimethy1-1,4-
diarrminobenzene, 2,3-dimethy1-1,4-diaminobenzene, 2-chloro-1,4-
diaminobenzene, 2-
methoxy-1,4-diaminobenzene,1-phenylamino-4-aminobenzene, 1-dimethylamino-4-
aminobenzene, 1-diethylamino-4-aminobenzene, 2-isopropy1-1,4-diaminobenzene, 1-
hydroxypropylamino-4-aminobenzene, 2,6-dimethy1-3-methoxy-1,4-diaminobenzene,
1-
amino-4-hydroxybenzene, 1-bis(beta-hydroxyethyl)amino-4-aminobenzene, 1-
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methoxyethylamino-4-aminobenzene, 2-hydroxymethy1-1,4-diaminobenzene, 2-
hydroxyethyl-
1,4-diaminobenzene, and derivatives thereof, and acid or basic salts thereof.
Also suitable are
various types of pyrimidines such as 2,3,4,5-tetraaminopyrimidine sulfate and
2,5,6-triamino-
4-pyrimidinol-sulfate. Preferred primary intermediates are p-phenylenediamine,
p-
aminophenol, o-aminophenol, N,N-bis(2-hydroxyethyl)-p-phenylenediamine, 2,5-
diaminotoluene, their salts and mixtures thereof
Couplers
If present, the color couplers may range from about 0.0001-10%, more
preferably
about 0.0005-8%, most preferably about 0.001-7% by weight of the total
alkalizer
composition. Such color couplers include, for example, those having the
general formula:
x,
R5 0 R2
R5 R3
R4
wherein R1 is unsubstituted hydroxy or amino, or hydroxy or amino substituted
with
one or more C1-6 hydroxyalkyl groups; R3 and R5 are each independently
hydrogen, hydroxy,
amino, or amino substituted with C1-6 alkyl, C1-6 alkoxy, or C1-6 hydroxyalkyl
group; and
R2, R4, and R6 are each independently hydrogen, C1-6 alkoxy, C1-6
hydroxyalkyl, or C1-6
alkyl. Alternatively. R3 and R4 together may form a methylenedioxy or
ethylenedioxy group.
Examples of such compounds include meta-derivatives such as phenols, catechol,
meta-
aminophenols, meta-phenylenediamines, and the like, which may be
unsubstituted, or
substituted on the amino group or benzene ring with alkyl, hydroxyalkyl,
alkylamino groups,
and the like. Suitable couplers include m-aminophenol, 2,4-diaminotoluene, 4-
amino, 2-
hydroxytoluene, phenyl methyl pyrazolone, 1,3-diaminobenzene, 6-methoxy-1,3-
diaminobenzene, 6-hydroxyethoxy-1,3-diaminobenzene, 6-methoxy-5-ethy1-1,3-
diaminobenzene, 6-ethoxy-1,3-diaminobenzene, 1-bis(beta-hydroxyethyl)amino-3-
aminobenzene, 2-methy1-1,3-diaminobenzene, 6-methoxy-1-amino-3-[(beta-
hydroxyethyl)aminol-benzene, 6-(beta-aminoethoxy)-1,3-diaminobenzene, 6-(beta-
hydroxyethoxy)-1-amino-3-(methylamino)benzene, 6-carboxymethoxy-1,3-
diaminobenzene.
6-ethoxy-1-bis(beta-hydroxyethyl)amino-3-aminobenzene, 6-hydroxyethy1-1,3-
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diaminobenzene, 3,4-methylenedioxyphenol, 3,4-methylenedioxy-1-Kbeta-
hydroxyethyDaminolbenzene, 1-methoxy-2-amino-4-[(beta-
hydroxyethyDamino]benzene,1-
hydroxy-3-(dimethylamino)benzene, 6-methyl-I -hydroxy-3[(beta-
hydroxyethyDaminolbenzene, 2,4-dichloro-1-hydroxy-3-aminobenzene, 1-hydroxy-3-
(diethylamino)benzene, 1-hydroxy-2-methy1-3-aminobenzene, 2-chloro-6-methyl-1-
hydroxy-
3-aminobenzene, 1-hydroxy-2-isopropyl-5-methylbenzene, 1,3-dihydroxybenzene. 2-
chloro-
1,3-dihydroxybenzene, 2-methy1-1,3-dihydroxybenzene, 4-chloro-1,3-
dihydroxybenzene, 5,6-
dichloro-2-methy1-1,3-dihydroxybenzene, 1-hydroxy-3-amino-benzene, 1-hydroxy-3-
(carbamoylmethylamino)benzene, 6-hydroxybenzomorpholine, 4-methyl-2, 6-
dihydroxypyridine, 2,6-dihydroxypyridine, 2,6-diaminopyridine, 6-
aminobenzomorpholine, 1-
pheny1-3-methy1-5-pyrazolone, 1-hydroxynaphthalene, 1,7-dihydroxynaphthalene,
1,5-
dihydroxynaphthalene, 5-amino-2-methyl phenol, 4-hydroxyindole, 4-
hydroxyindoline, 6-
hydroxyindole, 6-hydroxyindoline, 2,4-diamioniphenoxyethanol, and mixtures
thereof
Auxiliary Ingredients
Reducing Agents and Antioxidants
The alkalizer composition may further comprise one or more reducing agents
and/or
one or more antioxidants. Reducing agents and antioxidants are able to
stabilize the
composition by inhibiting reactions between the primary intermediates and
couplers as well as
the onset of oxidation through exposure to atmospheric oxygen. A commonly used
reducing
agent is sodium metabisulfite, which may be used in the range of 0.1% to 5%,
by weight of the
alkalizer composition. Water soluble antioxidants include erythorbic acid. If
the alkalizer
composition is an emulsion, then an oil-soluble antioxidant, such as t-
butylquinone may be
useful. Antioxidants may typically comprise 0.1% to 5% by weight of the
alkalizer
composition.
Emollient Oils
If desired the alkalizer composition may contain one or more emollient oils.
Such oils
will provide a conditioning effect to the hair. If present, such oils may
range from about 0.001
to 45% preferably from about 0.01 to 40%, more preferably from about 0.1 to
35% by weight
of the alkalizer composition. Suitable oils include silicones such as
dimethicone, phenyl
silicones, fatty alkyl silicones such as cetyl or stearyl dimethicone, or
silicone surfactants
which are generally referred to as dimethicone copolyols, or cetyl dimethicone
copolyol. Also
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suitable are various animal, vegetable, or mineral oils derived from plants or
animals, or
synthetic oils. Examples include oils from sunflower, castor seeds, orange,
lemon, jojoba,
mineral oil, and the like.
Surfactants
The alkalizer composition may comprise one or more surfactants. Suitable
surfactants
include well known cosmetically acceptable anionic, nonionic, amphoteric and
cationic
surfactants, and the like. If present, surfactants may range from about 0.001-
50%, preferably
about 0.005-45%, more preferably about 0.1-40% by weight of the alkalizer
composition.
Polar Solvents
The alkalizer composition may also comprise a variety of nonaqueous polar
solvents
other than water, including mono-, di-, or polyhydric alcohols, and similar
water soluble
ingredients. If present, such polar solvents may range from about 0.01-25%,
preferably about
0.05-15%, more preferably about 0.1-10% by weight of the first composition of
polar solvent.
Examples of suitable monohydric alcohols include ethanol, isopropanol, benzyl
alcohol,
butanol, pentanol, ethoxyethanol, and the like. Examples of dihydric or
polyhydric alcohols, as
well as sugars and other types of humectants that may be used, include
glycerin, glucose,
fructose, mannose, mannitol, maltitol, lactitol, inositol, and the like.
Suitable glycols include
propylene glycol, butylene glycol, ethylene glycol, polyethylene glycols
having from 4 to 250
repeating ethylene glycol units, ethoxydiglycol, and the like.
Chelating Agents
The alkalizer composition may optionally contain 0.0001-5%, preferably 0.0005-
3%,
more preferably 0.001-2% of one or more chelating agents which are capable of
complexing
with and inactivating metallic ions in order to prevent their adverse effects
on the stability or
effects of the composition. In particular, the chelating agent will chelate
the metal ions found
in the water and prevent these ions from interfering with the deposition and
reaction of the dye
with the hair fiber surface. Suitable chelating agents include EDTA and
calcium, sodium, or
potassium derivatives thereof, HEDTA, sodium citrate, TEA-EDTA, and so on.
pH Adjusters
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It may also be desirable to add small amounts of acids or bases to adjust the
pH of the
alkalizer composition to the desired pH range, such that the final on-hair
product has a pH of
from about 8 to about 12. Suitable acids include hydrochloric acid, phosphoric
acid, and the
like. Suitable bases include sodium hydroxide, ammonium hydroxide, potassium
hydroxide,
and the like, as well as the basic amino acids (arginine, lysine and
histidine). Also suitable are
primary, secondary, or tertiary amines and derivatives thereof such as
aminomethyl propanol,
monoethanolamine, and the like. Suggested ranges of pH adjusters are from
about 0.00001-
8%, preferably about 0.00005-6%, more preferably about 0.0001-5% by weight of
the total
alkalizer composition.
Botanical Ingredients
The alkalizer composition may comprise one or more botanical ingredients. If
present,
suggested ranges are from about 0.00001-10%, preferably from about 0.0001-8%,
more
preferably from about 0.0001-5% by weight of the total alkalizer composition.
Examples of
such ingredients include Camellia Sinensis extract, Camellia Oleifera extract,
Vanilla extract,
Green Tea extract, Aloe Barbadensis extract, and the like.
Container for the Alkalizing Composition
The alkalizer composition is preferably stored in a container that is air-
tight and made
of a material that is oxidation resistant. Preferably such containers are in
the form of tubes,
jars, bottles, and the like. Preferred, is where the container is a tube,
preferably a tube that can
be compressed to dispense the alkalizer composition found therein. Suitable
tubes may be
metallic. Preferred is where the tube is an oxidation resistant aluminum. In
the most preferred
embodiment, the tube is made from oxidation resistant aluminum haying less
than 100 ppm of
cadmium, mercury, lead, and hexavalent chromium. The closure for the container
of the
alkalizer composition must prohibit air from oxidizing the contents of the
container. A variety
of closures are suitable including screw caps, snap off lids, and the like.
Preferably the closure
is reusable in the event that multiple uses are desired, for example, in a
salon environment.
Once the container is opened it may be used to dispense the desired amount of
alkalizer
composition as needed. The container may be re-closed, and stored for hours,
days, weeks, or
even months, before the remaining contents are used. An alkalizer composition
formulated
according to the invention and stored in a suitable container can be used, and
the remaining
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contents stored indefinitely. For example, including an antioxidant in the
alkalizer
composition will enable the container of oxidative hair dye to be used and
stored from 1-6
days, or from 1 to 3 weeks, or from 1 to 4 months before it is used again.
II. The Oxidizing Agent Composition
Immediately prior to application to hair, the alkalizer composition of the
invention is
combined with an oxidizing agent composition to form a hair-dyeing
composition. Aqueous
forms of the oxidizing agent composition contain water, generally in an amount
ranging from
about 65% to 99%, preferably from about 70 to 97%, most preferably from about
70% to 94%
by weight of the oxidizing agent composition. Aqueous forms of the oxidizing
agent
composition may include lotions, creams and gels. Anhydrous forms of the
oxidizing agent
composition are sometimes used (powders, for example). In addition, the
oxidizing agent
composition also comprises an oxidizing agent that will react with the
precursor dyes present
in the alkalizer composition. Most often the oxidizing agent used is hydrogen
peroxide, but
other peroxides or oxidizing agents may be used such as calcium peroxide,
sodium
percarbonate and one or more persulfates (i.e. ammonia, potassium and sodium).
Preferably
the hydrogen peroxide concentration in the oxidizing agent composition ranges
from about 1
to 20% by weight of the oxidizing agent composition.
The oxidizing agent composition may typically comprise peroxide stabilizers,
such as
sodium stannate and pentasodium pentetate. Alternatively, some type of
chelating system may
be used to maintain the relatively low pH of the oxidizing agent composition.
Stabilizers
and/or chelating system may comprise 0.01% to 5.0% by weight of the oxidizing
agent
composition.
IV. Testing of Alkalizer Compositions
The alkanolamines in Table 1 were tested in a base dye composition (having no
dyes,
nor dye precursors) to evaluate their suitability as alkalizers. The alkalizer
compositions
according to the invention, as well as control compositions, were subjected to
various
analytical techniques, including thermodynamic, optical and tensile analysis,
and cytotoxicity
testing.
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Hair Sample Preparation
Level 4 mixed-source human hair tresses were purchased from International Hair
Importers & Products, Inc (New York). Testing was performed on virgin hair
(control), hair
that had been treated with ammonium hydroxide, and hair that had been treated
with various
single alkalizer compounds and combinations thereof, as described herein. Ten
grams of
freshly made alkalizer composition were mixed with 10 grams of volume 40 (12%)
oxidizer
developer (Aveda Color Catalyst Conditioning Creme Developer) until a
homogenous cream
was obtained. The ammonium hydroxide samples were also mixed with volume 40
oxidizer
developer. Approximately 4 grams of cream mixture per gram of hair was applied
to sample
hair tresses. Each hair tress was then incubated at 37 C oven for 45 minutes.
The hair tresses
were rinsed with tap water for 1 minute before applying SDS (sodium dodecyl
sulfate) 5%
solution. Each hair tress was massaged for 30 seconds in SDS solution. The
hair tresses were
rinsed again with tap water for 1 minute to wash off all surfactant. The
treated tresses were
blown dry with a hair dryer on medium/high speed with medium/high heat.
Thereafter, the
tresses were allowed to air dry at room temperature for 12 hours, before being
subjected to
differential scanning calorimetty (DSC) and spectrophotometric analysis.
Alkalizer Compositions Tested
The following base alkalizer composition (without dyes or dye precursors) was
used to
test each alkalizing agent or combinations thereof
Table 2
Base alkalizer composition
INCI Name Percent
Cocamide MEA 10.00
Glyceryl stearate 4.00
Cetearyl alcohol 2.50
Steareth-21 2.50
Euphorbia cerifera 2.00
(candelilla) wax
Oleic acid 1.00
Decyl glucoside 5.00
Glycerin 2.00
Erythorbic acid 0.20
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Tetrasodium EDTA 0.40
Sodium sulfite 0.20
Water q.s.
Table 3 shows the amount of each individual alkalizer that was added to one
composition of Table 2 to complete an alkalizer composition. Also shown are
the pH,
viscosity and alkalinity of the alkalizer composition. The Brookfield LVDVII
Pro Viscometer
was used to measure the viscosity of the formulation. The measurements were
performed at
22 C with T-F spindle at 6 rpm. All compositions contain the same molar
percentage of
alkalizer, the water content being adjusted accordingly. Ammonium hydroxide,
being the gold
standard in alkalizers, serves as a control, and MEA and AMP as common
replacements for
ammonium hydroxide are included for comparison.
Table 3
Percent (by weight
Vi scosity
Alkalinity
Alkalizer of total alkalizer pH
(cP x 105)
(mug)
composition)
Ammonium hydroxide 6.90 10.72 5.11
2.32
(29%)*
MEA (99%)* 7.17 10.85 3.02
2.35
AMP (95.5%)* 10.84 10.91 1.81
2.32
DMAMP (78%)* 17.46 11.15 0.211
2.38
AMPD 12.30 10.28 3.84
2.49
AEPD (97%)* 16.58 10.33 4.47
2.40
AP 8.80 11.49 3.26
3.10
DMAP 12.08 10.58 2.77
2.32
DMAPD 14.10 10.37 3.23
2.57
lsoserinol 10.78 10.56 3.75
2.45
Serinol (97%)* 11.11 10.22 10.1
2.55
DEA 12.44 10.35 5.09
2.57
TEA 17.63 9.18 2.02
2.74
Tris 14.35 9.6 4.17
2.43
* percent active
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Various binary combinations of alkalizers were also tested by combining them
into the
base composition shown in Table 2.
DSC Analysis
Protein denaturation occurs when proteins lose their secondary, tertiary or
quaternary
structure by application of some external stress or compound, such as a strong
acid or base, a
concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform),
or heat, while the
peptide bonds between the amino acids (primary structure) are left intact.
Denaturation of
tertiary structure includes disruption of interactions between amino side
chains, such as
covalent disulfide bridges between cysteine groups, non-covalent dipole-dipole
interactions
between polar groups, and Van der Waals interactions between non-polar groups
in the side
chains. Denaturation of secondary structure means that proteins lose all
regular repeating
patterns (such as alpha-helix structure and beta-pleated sheets), and adopt a
random coil
configuration.
It is known that the denaturation of keratin in hair can be detected by
differential
scanning calorimetry. DSC is a thermal analysis technique used to measure
transition
temperature and heat of transformation (enthalpy) for endothermic and
exothermic reactions.
DSC is typically used to measure melting and solidification temperatures at
different melting
or cooling rates. DSC is sensitive enough to provide information about
molecular weight
distributions of polymers.
Denaturation measurements were made on virgin hair (control), hair that had
been
treated with a mixture of ammonium hydroxide and volume 40 oxidizer developer
(control),
and hair that had been treated with various alkalizer compounds (including
volume 40 oxidizer
developer), as described above. Also included, for comparison purposes, are
hair samples
treated with NaOH, which, above a certain concentration, is a very potent
alkalizer that
induces significant damage in human hair. NaOH is included as a worst damage
level
indicator.
Measurements were performed using the Mettler Toledo DSC822e (from Mettler
Toledo LLC, Columbus OH), or Discovery DSC 2500 (from TA Instruments. New
Castle,
DE). The experiments were carried out over a temperature range of 25 C to 180
C, with a
scan rate of 5 C/min under nitrogen protection. DSC samples were prepared by
cutting tress
samples into pieces (0.1 to 1.0 mm in size) and weighing. The hair samples
were mixed with
deionized water, and then sealed in high volume pans for at least 6 hours
before measuring.
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The phase transition temperature (keratin denaturation temperature) of each
hair sample was
analyzed using either STARe software (Mettler Toledo DSC822e) or TRIOS
software
(Discovery DSC 2500). Each hair sample was analyzed at least twice, and the
average
temperature was obtained for data analysis. A higher denaturation temperature
indicates that
less damage was incurred by the hair as a result of treatment with the mixture
of alkalizer
composition and oxidizer developer. Results are given in Tables 4A and 4B.
Table 4A - DSC; single alkalizer compositions
AT
% Relative damage level
Denaturation (change in
Damage level
Alkalizer Temperature denaturation compared to NaOH
normalized to
(TVirgin - TAlkalizer ) /
( C) temperature)
NH3.1-120
(TVirgin - TNa0H)
TVirgin - TAlkali7er
Virgin Hair 150.42 -- -- --
NH3-H20 147.63 2.79 19.52 % 1
(29%)
NaOH 136.13 14.29 100%
5.12
MEA 141.96 8.46 59.20 %
3.03
AMP 141.83 8.59 60.11 %
3.08
DMAMP 147.84 2.58 18.05 %
0.92
(85%)
AMPD 145.88 4.54 31.77 %
1.63
AEPD (97%) 146.25 4.17 29.18 %
1.49
AP 138.42 12 83.97%
4.30
DMAP 147.80 2.62 18.33 %
0.94
DMAPD 149.46 0.96 6.72 %
0.34
Isoserinol 144.59 5.83 40.80 %
2.09
Serinol 147.23 3.19 22.32%
1.14
(97%)
DEA 148.63 1.79 12.53 %
0.64
TEA 150.89 -0.47 -3.29 % -
0.17
Tris 149.00 1.42 9.94%
0.51
The above results may be interpreted in terms structure, intramolecular
hydrogen
bonding and shielding of the amine group. Table 4B lists the thirteen
alkanolamine alkalizers
in order from lowest denaturation temperature to highest. In order of
importance, the
characteristics that may explain the results are the order of the amine
(primary, secondary,
tertiary); number of OH groups, how many carbon atoms away the OH groups are
from the
amine, whether or not the nitrogen is flanked by OH and methyl groups.
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Table 4B - DSC; single alkalizer compositions
OH group(s):
Flanking of
Number of number of C
Alkalizer Amine order amine by OH
OH groups atoms away
groups
from amine
AP primary 1 3 no
AMP primary 1 2 no
MEA primary 1 2 no
Isoserinol primary 2 2,3 partial
AMPD primary 2 2,2 yes
AEPD (97%) primary 2 2,2 yes
Serinol
(97%) primary 2 2,2 yes
Below this line, treated hair samples showed a higher denaturation
temperature than samples treated with ammonium hydroxide
DMAP tertiary 1 3 no
DMAMP
(85%) tertiary 1 2 no
DEA secondary 2 2,2 yes
Tris primary 3 2,2,2 yes
DMAPD tertiaiy 2 2,3 partial
TEA tertiary 3 2,2,2 yes
The above results also indicate that AP (3-amino-1-propanol) was the only
alkalizer
that produced significantly more damage than either of the common replacements
for
ammonium hydroxide, MEA and AMP. Noticeably, MEA and AMP caused roughly 3 fold
higher damage than ammonium hydroxide. Serinol and DMAP performed the closest
to
ammonium hydroxide, making them suitable replacements for all, most or some of
the
ammonium hydroxide, at least in terms of denaturation temperature of the hair.
All of the hair samples treated with primary amine alkalizer compositions
(except for
Tris) show a lower denaturation temperature than the sample treated with an
ammonium
hydroxide composition, although hair sample treated with Serinol shows only a
slightly lower
denaturation temperature. However, among the primary amine alkalizers, AMPD,
AEPD,
isoserinol and Serinol performed significantly better than MEA and AMP, and
may therefore,
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be considered useful for softening and swelling the cuticle of the hair, and
for enabling
penetration of reagents and hair-benefit actives into the cortex.
Within the primary amine alkalizers, those with two OH groups performed better
than
those with only one. Within each of those subgroups, those wherein the OH
group or groups
were, on average, closer to the amine performed better. Here, the term
"closer" means fewer
number of intervening carbon atoms. Also of note is whether or not the amine
is -flanked" by
two or more OH groups within two carbon atoms. The amines in Isoserinol and
DMAPD are
flanked by two OH groups, but only one of the OH groups is within two carbon
atoms.
All of the tertiary and secondary amine alkalizer compositions (TEA, DMAPD,
DEA,
DMAMP and DMAP) were less damaging to hair than the ammonium hydroxide
composition. Tris, a primary amine alkalizer, also performed well. Among all
of these
alkalizers, those with two or three OH groups performed better than those with
only one.
Among the secondary and tertiary amine alkalizers, those with more OH groups
performed
better. Tris is a special case. As a primary amine Tris might have been
expected to perform
less well. However, having three OH groups all within two carbon atoms of the
amine, and
partial flanking seems to have contributed to its performance. TEA produced
the least damage
to the tested hair sample, but a residual coating may form on the hair
surface. The following
generalization can be made: when the objective is to limit damage to hair,
then primary
alkanolamines with at least two OH groups, as well as secondary and tertiary
alkanolamines,
are preferred.
It seems that at least some of the performance of each alkalizer can be
attributed to
stabilizing or shielding of the amine group as a result of intramolecular
hydrogen bonding,
especially between the hydrogens of the hydroxyl groups and nitrogen, although
some other
hydrogen bonding or other effects may also be occurring. In fact, the only
difference between
AP (the worst performer in DSC testing) and DMAP (a better performer than
ammonia) is the
two methyl groups on the amine of DMAP, which appear to be stabilizing the
amine to a
significant degree.
Color Lifting
Spectrophotometry was used to evaluate changes in color and changes in the
appearance of various hair samples, as a result of exposure to various
alkalizer compounds and
combinations thereof, as described herein. Spectrophotometry can be used to
measure the
light reflected from a given surface or object. Konica Minolta CM-600d
Spectrophotometer
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and accompanying SpectraMagic NX software were used to collect data for
evaluation of hair
tress color. The standard is to express color as three different numerical
values (L*, a*, and
b*). The values are intended to mimic what is perceived by the human eye. The
a* value,
which represents the red/green color of the hair sample, and the b* value,
which represents the
yellow/blue color of the hair sample, are not reported, here. The L* value,
however,
represents the light/dark intensity of the measurement surface. L* values
range from 0 to 100,
where 0 is pure black and 100 is pure white. The higher the L* value, the
lighter the hair
color, and the more effective the alkalizer at lifting natural hair color.
Measurements of L*
were made on virgin hair (control), hair that had been treated with a mixture
of ammonium
hydroxide and volume 40 oxidizer developer (control), and hair that had been
treated with
various alkalizer compounds (including volume 40 oxidizer developer), as
described above.
Also included, for comparison purposes, are hair samples treated with NaOH,
which, above a
certain concentration is a very potent alkalizer that is expected to induce a
significant loss of
melanin. Each hair tress was bound on one end to form a swatch wherein the
hair is uniformly
distributed along the binding. The measured values of L* are given in Table 5.
Table 5 - L Values; single alkalizer compositions
AL Relative lifting level in
Lifting level
Alkalizer L Value (change in color
percentage
normalized
lifting) (LVirgin -
LAIkalizer)/(LVirgin ¨
to NI-13.f120
LVirgin - LAIkalizer LNa0F1)
Virgin 19
NH3-H20 34 -15 85.23% 1
(29%)
NaOH 36.6* -17.6 100%
1.17
AP 37 -18 102.27%
1.20
MEA 36 -17 96.59%
1.13
Isoserinol 36 -17 96.59%
1.13
AMP 32.5 -13.5 76.70%
0.90
AMPD 32 -13 73.86%
0.87
Serinol 31 -12 68.18%
0.80
(97%)
DEA 30.5 -11.5 65.34%
0.77
AEPD 30 -11 62.50%
0.73
(97%)
DMAP 27 -8 45.45 %
0.53
Tris 27 -8 45.45 %
0.53
DMAPD 25.5 -6.5 36.93 %
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DMAMP 26 -7 39.77 %
0.47
(85%)
TEA 23 -4 22.73 %
0.27
The results show that the isoserinol/oxidizer mixture and the 3-amino-l-
propanol
(AP)/oxidizer mixture are better at lifting natural hair color than the
ammonium
hydroxide/oxidizer mixture (and even similar to or better than NaOH).
Furthermore,
isoserinol displayed about the same effectiveness as MEA, and significantly
better
effectiveness than AMP, the two common replacements for ammonium hydroxide. 3-
amino-
1-propanol (AP) outperformed all of them. The other compositions were less
effective at
lifting hair color than ammonium hydroxide, MEA and AMP. However, AMPD was
almost
as good as MEA and ammonium hydroxide. In terms of color lifting, serinol and
DMAP,
which compared well to ammonium hydroxide vis-a-vis damage, performed
significantly less
well than ammonium hydroxide. This may suggest a combination of alkalizing
agents, such as
ammonia, MBA or isoserinol combined with serinol or DMAP, to obtain the
benefits of both
The color lifting results are roughly reversed from the DSC results above in
that all of
the primary amine alkalizer compositions performed better than the tertiary
amine alkalizer
compositions, except that Tris was as good as tertiary alkalizer DMAP. Also
the primary
amine alkalizer, AEPD, was not quite as good as secondary amine alkalizer,
DEA, but close.
Testing Combinations of Alkalizers
We surmised that combinations of alkalizers are likely to combine the benefits
of each
while mitigating the drawbacks. Based on the above results, select binary
combinations of
alkalizers were also tested by combining two alkalizer compositions made
according to Tables
2 and 3. The first set of combinations all involve NH3, as follows: AMPD-NH3,
AEPD-NH3,
DMAMP-NI-13, Tris-NH3 and Serinol-NH3. These combinations were tested in
different mole
ratios as shown in the tables 6-10, below.
Table 6- AMPD-NI-13
Denaturation
Mole ratio AMPD/NH3 L* value
Temperature ( C)
100% AMPD 143.45 32.1
90/10 143.41 31.6
67/33 143.77 32.7
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50/50 143.80 31.5
33/67 144.30 32.4
10/90 144.34 32.1
100% NH3 144.10 33.6
Virgin hair 146.76 20.0
Table 7 AEPD-NH3
Denaturation
Mole ratio AEPD/NH3 L* value
Temperature ( C)
100% AEPD 146.25 30
75/25 146.54 32.9
50/50 147.39 33.3
25/75 146.96 32
100% NH3 146.92 33
Virgin hair 149.84 20.2
Table 8A DMAMP-NH3
Denaturation
Mole ratio DMAMP/N113 L* value
- Temperature ( C)
100% DMAMP 147.84 26
75/25 144.89 27
70/30 147.92 29
60/40 147.63 29
50/50 147.11 32
40/60 146.84 32,5
25/75 148.55 33.5
10/90 148.04 33.9
100% NH3 145.83 34
1
Virgin hair 50.05 20.3
Table 8B DMAMP-NH3 in low DMAMP percentages
Denaturation
Mole ratio DMAMP/NH3 L* value
Temperature ( C)
100% DMAMP 145.67 24.9
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35/65 144.94 32.4
30/70 144.29 31.5
25/75 144.72 32.1
20/80 144.71 32.9
15/85 145.27 32.9
10/90 145.02 33.1
9/91 145.12 32.5
8/92 144.95 33.8
7/93 145.08 32.4
6/94 145.03 33.6
5/95 145.31 32.5
4/96 144.52 33.7
3/97 144.76 34.1
2/98 144.52 32.6
1/99 144.53 33.0
0.5/99.5 144.26 33.3
100% NH3 144.17 33.8
Virgin hair 148.12 20.3
Table 9 Tris-N1-13
Mole ratio Tris/NH3 Denaturation L* value
Temperature ( C)
100% Tris 148.61 28
90/10 148.29 30
67/33 148.00 32
50/50 147.61 33
33/67 146.92 33
10/90 147.63 33.5
100% NH3 146.75 34
Virgin Hair 149.33 20.0
Table 10 Serinol-NH3
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Mole ratio Serinol/NH3 Denaturation L* value
Temperature ( C)
100% Serino' 143.50 31.2
90/10 143.70 32.3
67/33 143.53 32.4
50/50 143.34 32.2
33/67 143.54 34.2
10/90 143.61 34.4
100% NH3 143.75 35.2
Virgin hair 146.14 19.9
Table 11 AMPD-Tris
Mole ratio AMPD/Tris Denaturation L* value
Temperature ( C)
100% AMPD 146.78 31
90/10 146.86 31
67/33 146.75 29
50/50 147.33 29.2
33/67 148.17 29
10/90 148.59 28.5
100% Tris 148.61 28
Virgin hair 150.75 20.3
Table 12 AEPD-Tris
Mole ratio AEPD/Tris Denaturation L* value
Temperature ( C)
100% AEPD 142.76 30.4
90/10 142.28 30.3
67/33 142.90 31.6
50/50 143.45 31.1
33/67 144.54 29.8
10/90 145.89 29.8
100% Tris 145.93 28.5
Virgin hair 146.70 20.4
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Table 13 Serinol-Tris
Denaturation
Mole ratio Serinol/Tris L* value
Temperature ( C)
100% Serinol 144.78 31.2
90/10 144.89 31.2
67/33 145.53 31.4
50/50 145.72 30.6
33/67 145.81 28.1
10/90 146.91 28.4
100% Tris 146.81 28.5
1
Virgin hair 46.70 20.4
The addition of AMPD, AEPD or Serinol to NH3 lowered the denaturation
temperature, but only slightly. The addition of DMAMP or Tris to NH3 raised
the
denaturation temperature. Almost any amount of Tris lead to less damage than
AMPD, AEPD
or Serinol alone, and less damage than AMPD, AEPD or Serinol in combination
with NH3.
In those combinations involving NH3, the L* value decreased somewhat,
indicating less
efficient lifting than 100% NH3. Tris tends to reduce the effectiveness of
color lifting.
The denaturation temperature of each mixture of alkalizers varies
approximately linear
with the relative concentration of each alkalizer. The combination of DMAMP-
NH3 is an
exception. In that case, there are two clusters of data (see the figure). A
first cluster of
temperature data exists between about 0 and 15 molar percentage of DMAMP. A
second
cluster exists between about 25 and 100 molar percentage of DMAMP. DMAMP-NH3
exhibited a significant increase in denaturation temperature when going from
100% NH3 to
0.5:99.5 (1:199 DMAMP:NH3). This result was unexpected. This non-linear
relationship is
indicative of a range of molar percentages in which color lifting increases
with little additional
denaturation. We justifiably expect therefore, beneficial results for mole
ratios in between
100% NH3 and 3:7 (DMAMP:NH3). For example, mole ratios (DMAMP:NH3) of 1:199,
1:99,
1:90, 1:45, 1:30, 1:22.5, 1:18, 1:15, 1:12.9, 1:11.25, 1:3 and 1:2.5 are
useful because of
significantly less damage compared to 100% NH3. A mole ratio between 1:99 and
1:2.5 is
preferred; between 1:45 and 1:4 is more preferred; between 1:20 and 1:3 is
still more
preferred.
In total, the above data suggests the existence of preferred ranges of the
relative
concentration for each combination of alkalizers, depending on the effect
sought. A summary
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of DSC results is shown in Table 14. Also shown are preferred ranges of the
mole ratio for
each combination of alkalizers, based on DSC results alone, and based on DSC
and L* value
results.
Table 14- Combinations of Alkalizers
Preferred range of Preferred
range of
Combination Overall DSC result mole ratio based on mole
ratio based on
DSC alone DSC and
L* value
AMPD-NH3 certain concentrations about 1:1 to about 1:9
about 1:1 to about
showed improvement over 1:9
100% NH3
AEPD-NH3 up to 50% AEPD showed about 1:1 to about 1:3 about
1:1 to about
improvement over 100% 1:3
NH3
DMAMP-NH3 all concentrations showed about 1:199 to about about
1:199 to about
improvement over 100% 100% DMAMP 1:4
NI-13
Tris-NH3 all concentrations showed about 1:9 to about
about 1:9 to about
improvement over 100% 100% Tris 2:1
NH3
Serinol-NH3 All concentrations were about 1:99
to about about 1:2.5 to about
very similar to 100% NH3 100% Serinol 1:9
AMPD-Tris all concentrations of Tris about 9:1
to about about 9:1 to about
showed improvement over 100% Tris 1:99 Tris
100% AMPD
AEPD-Tris Almost all concentrations about 9:1
to about about 9:1 to about
of Tris showed 100% Tris 1:99 Tris
improvement over 100%
AEPD
Serinol-Tris all concentrations of Tris about 9:1
to about about 9:1 to about
showed improvement over 100% Tris 1:99 Tris
100% Serinol
Cytotoxi city
The effects of alkalizer compositions on outer root sheath cells and on
keratinocytes
was evaluated. The MultiTox-Fluor Multiplex Cytotoxicity Assay (Promega Corp.,
Madison,
WI) simultaneously measures two protease activities: one is a marker of cell
viability, and the
other is a marker of cytotoxi city. In the assays, the responses of outer root
sheath cells and
keratinocytes to various concentrations of alkalizers were measured, and IC
50, the
concentration that provokes a mid-height response (midway between the baseline
response and
maximal response), was determined. In this study, a greater ICso value
indicates that the
alkalizer induces less stress on the cells. The results are shown in Table 15.
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Table 15 Toxicity
IC50 Outer root 1C5o
Alkalizer
sheath cells Keratinocytes
NE14.0H (29% active) 54.63 45.18
(control)
MEA 21.43 23.00
AMP 11.87 5.197
DMAMP 18.00 33.00
AMPD 103.6 106.1
AEPD (97%) 87.00 121.0
3-(dimethylamino)-1,2- 124.0 212.0
propanediol
Isoserinol 56.27 97.00
For either type of cell, conventional replacements for ammonia, MEA and AMP
are
more toxic to the cell than ammonium hydroxide. DMAMP is also more toxic than
ammonium hydroxide, but less toxic than conventional replacement AMP, and less
toxic to
keratinocytes than MEA. Also, for either type of cell AMPD, AEPD, DMAPD and
isoserinol
are significantly less toxic than ammonium hydroxide.
Tensile Strength
The effects of alkalizer compositions on the tensile strength of hair fibers
was
measured. Hair tresses were treated with the compositions shown in Tables 2
and 3, as
described above. From each tress, multiple individual hair fibers were
prepared for tensile
analysis using brass crimps and a Diastron AAS 1600 (Diastron Ltd, UK) to
thread and crimp
the hair. The mean cross-sectional area of each fiber was determined using a
laser micrometer
FDAS 770 unit (Diastron Ltd, UK) at 24 C and 55% relative humidity (RH). All
hair fibers
were stretched until break using a Diastron MTT 686 instrument with control
unit UV1000
(Diastron Ltd, UK). Final results were calculated by software analysis (UvWin
2.35.0000,
Diastron, Ltd, UK). The average applied stress at break is shown in Table 16.
A greater stress
at break indicates that the hair fibers were less weakened by the applied
alkalizer composition.
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Table 16 Break Stress (gmf/sq micron)
NH3 MEA AMP DMAMP AMPD AEPD AP
Average 2.19E-02 2.11E-02 2.10E-02 2.16E-02 2.19E-02 2.17E-02 2.11E-02
Std. Dev. 1.32E-03 1.47E-03 1.47E-03 1.67E-03
1.25E-03 1.42E-03 1.37E-03
ii 49 49 49 49 46 48 49
T-test
0.004 0.001 0.234 0.990 0.332 0.004
(vs. NH3)
Break Stress (gmf/sq micron)
DMAP DMAPD Isoserinol Serino' DEA TEA Tris
Average 2.21E-02 2.19E-02 2.17E-02 2.12E-02 2.13E-02 2.19E-02 2.18E-02
StdDev 1.59E-03 1.49E-03 9.83E-04 1.37E-03 1.66E-03 1.34E-03 1.66E-03
50 50 48 48 47 48 50
T-test
0.555 0.943 0.316 0.009 0.053 0.847
0.760
(vs. NH3)
The tensile data in Table 16 shows the average break stress for hair fiber
after
treatment with the alkalizing composition and oxidant. The samples are
compared to NH3 as
the baseline. The break stress data indicate that, as a general trend that
going from primary to
tertiary amine decreases the amount of damage. For example, the tertiary
amines (DMAMP,
DMAP, DMAPD, TEA) cause a similar amount of damage or less damage than their
primary
amine analogs (AMP, AP, AMPD, MEA). Also, going from primary to secondary to
tertiary
decreases the amount of damage seen with MEA, DEA, and TEA. Furthermore, the
data also
show that the location and number of hydroxyl groups impacts the tensile
strength, as seen
when comparing AP vs AMP vs AMPD. The introduction of two hydroxyl groups
(AMPD)
surprisingly results in a less damaged hair fiber. A similar effect is
observed with Tris which
is a primary amine flanked by 3 hydroxyl groups. Both of these examples
demonstrate fiber
damage similar to NH3 with comparable lift.
Odor Evaluation
A professional perfumer ranked several of the alkalizer compositions
represented in
tables 1 and 2. The base formula (Table 1) with no alkalizer was used as a
control. Among
the primary alkanolamine compositions, the order from no malodor to strongest
malodor was:
Control > AMPD = Serinol > Tris > MEA = AMP > AEPD > NH3
Among the tertiary alkanolamine compositions, the order from no malodor to
strongest
malodor was:
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Control > DMAMP > DMAPD > NH3
All of the alkanolamine compositions that were evaluated have less malodor
than the
ammonium hydroxide composition. Among the primary amines, AMPD, Serinol and
Tris
performed better than MEA and AMP, two conventional ammonia replacements. The
two
tertiary amines tested did not perform as well as MEA and AMP.
Example
Table 17
Alkalizer Color lifting
composition composition
with dye
INCI Name Percent Percent
Cetearyl alcohol 2.00-10.00 2.00-10.00
Steareth-21 1.00-4.00 1.00-4.00
Sunflower oil 2.00-3.00 2.00-3.00
Decyl glucoside 0.10-5.00 0.10-5.00
Glycerin 1.00-3.00 1.00-3.00
Antioxidant 0.50-1.00 0.50-1.00
Tetrasodium EDTA 0.30-0.50 0.30-0.50
Oxidative dye 0.01-25.0
DMAMP compound 0.50 0.50
(80% active)
Ammonium hydroxide 4.00 16.00
(29% active)
Aroma 0.01-1.00
Water q.s. q.s.
In summary, six of the eleven alkanolamines performed well in the DSC
analysis,
suggesting a reduction in hair fiber damage compared to ammonium hydroxide.
Eight of the
eleven alkanolamines performed comparably to NH3 in the tensile test. In DSC
analysis, ten
of the eleven alkanolamines, when used as hair colorant alkalizers,
demonstrated a reduction
in hair fiber damage over MEA and AMP, conventional replacements for ammonium
hydroxide. In tensile strength analysis, eight of the eleven alkanolamines,
when used as hair
colorant alkalizers, demonstrated a reduction in hair fiber damage over MEA
and AMP. Three
alkanolamines were better than ammonium hydroxide at lifting color from hair.
One of these
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(isoserinol) was significantly better than AMP and about the same as MEA, at
lifting hair
color. Furthermore, combinations of the eleven alkalizers, with or without
ammonium
hydroxide, have proved beneficial in regard to reduction of hair damage,
improved color
lifting, or both. We have discovered that, for a mixture of two alkalizers,
keratin denaturation
temperature varies roughly linearly with the relative concentration of each
alkalizer, except in
the case of DMAMP-NH3. This result was unexpected. This, combined with L*
value
measurements, suggests the existence of a preferred range of the relative
concentration for
each combination of alkalizers, and we have identified these.
Primary alkanolamines smell better than tertiary alkanolamines. For outer root
sheath
cells and keratinocyte, MEA, AMP and DMAMP are more toxic to the cell than
ammonium
hydroxide. However, for either type of cell AMPD, AEPD, DMAPD and isoserinol
are
significantly less toxic than ammonium hydroxide. Some or all of these
properties may be
beneficial in both oxidative and non-oxidative hair treatments.
In general, we have demonstrated the suitability of various alkanolamines for
softening
and swelling of the hair cuticle, for enabling penetration of reagents and
hair-benefit actives
into the cortex. These results are useful for various types of hair treatment
applications, but
we have specifically demonstrated the case of hair coloring treatments. We
have shown that
the use of ammonium hydroxide can be reduced or eliminated, depending on the
type of hair
coloring application.
Discussion
Based on observations, it may be surmised that intra-molecular hydrogen
bonding
within the alkanolamines results in conformations that provide some degree of
stabilizing of
the amine. Of foremost interest is the hydrogen bonding between the nitrogen
atom and one or
more hydroxyl groups of the alkanolamine. This type of intra-molecular bonding
offers an
explanation for the variation that we have observed in regards to hair fiber
denaturation and
color lifting. In general, the more hydrogen bonding in which the amine
participates, the less
damage experienced by the hair, but at the cost of less effective color
lifting. However, of
specific interest are those alkanolamine molecules wherein the electron bond
donors are
located at exactly two carbons away from the nitrogen atom. Those primary
alkanolamines
that have two or more hydroxyl groups located in C2 positions are useful
alkalizers in hair
treatment products. Also, secondary and tertiary alkanolamines that have at
least one hydroxyl
group located in a C2 position are useful.
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While particular embodiments of the present invention have been illustrated
and
described, it would be obvious to those skilled in the art that various other
changes and
modifications can be made without departing from the spirit and scope of the
invention. It is
therefore intended to cover in the appended claims all such changes and
modifications that are
within the scope of this invention.
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